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Predicting the risk of recurrent adenoma and incident colorectal cancer based on findings of the baseline colonoscopy.

ABSTRACT: OBJECTIVES: The decision tree underlying current practice guidelines for post polypectomy surveillance relies on risk stratification based on predictive attributes gleaned from adenomas removed on screening colonoscopy examination. Our primary aim was to estimate the magnitude of association between baseline adenoma attributes and the risk of adenoma recurrence and invasive colorectal adenocarcinoma (CRC). Our secondary aims were to estimate the adenoma detection rate (ADR) of surveillance compared with screening colonoscopies and describe time trends in preventive colonoscopy utilization. METHODS: We used prospective analyses of retrospectively collected clinical data from electronic health records. A cohort of primary care patients eligible for colorectal cancer screening was assembled encompassing 110,452 subjects, of which 3,300 had adenomas removed on screening examination. Of those patients who had a follow-up surveillance colonoscopy (defined as a patient with a documented adenoma on prior colonoscopy) recorded during the study period, 537 had a recurrent adenoma. RESULTS: Of those recurrent adenomas, 354 had a high-risk attributes. High-risk attributes were described at >3 adenomas, at least one adenoma >10 mm in size, high-grade dysplasia, or villous features. The risk of developing invasive CRC among post polypectomy patients was significantly higher if the baseline adenomas displayed any of the following attributes: more numerous than 3 (4.3-fold higher risk, 95% confidence interval (CI) low, high 1.4, 12.9), larger than 10 mm in size (5.2-fold higher risk, 95% CI low, high 1.8, 15.1), high-grade dysplasia (13.2-fold risk, 95% CI low, high 2.8, 62.1), or villous features (7.4-fold higher risk, 95% CI low, high 2.5, 21.5). These attributes combined added a net value of 22.8% to the probability of correctly predicting CRC. There was a threefold increase in surveillance utilization relative to screening from 2005 to 2011. The ADR of surveillance (34.1%) was 1.5-fold higher than that of screening (23.1%). CONCLUSIONS: These results emphasize the need to mitigate excessive risk by performing timely surveillance colonoscopies in patients with baseline adenomas displaying high-risk attributes as recommended in practice guidelines.

SUBMITTER: Fairley KJ

PROVIDER: S-EPMC4274367 | biostudies-other | 2014

REPOSITORIES: biostudies-other

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Project description:ImportanceIndividuals with adenomatous polyps are advised to undergo repeated colonoscopy surveillance to prevent subsequent colorectal cancer (CRC), but the relationship between adenomas at colonoscopy and long-term CRC incidence is unclear.ObjectiveTo compare long-term CRC incidence by colonoscopy adenoma findings.Design, setting, and participantsMulticenter, prospective cohort study of participants in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer randomized clinical trial of flexible sigmoidoscopy (FSG) beginning in 1993 with follow-up for CRC incidence to 2013 across the United States. Participants included 154 900 men and women aged 55 to 74 years enrolled in PLCO of whom 15 935 underwent colonoscopy following their first positive FSG screening result. The final day of follow-up was December 31, 2013.ExposuresEnrolled participants had been randomized to FSG or usual care. Participants who underwent FSG and had abnormal findings were referred for follow-up. Subsequent colonoscopy findings were categorized as advanced adenoma (≥1 cm, high-grade dysplasia, or tubulovillous or villous histology), nonadvanced adenoma (<1 cm without advanced histology), or no adenoma.Main outcomes and measuresThe primary outcome was CRC incidence within 15 years of the baseline colonoscopy. The secondary outcome was CRC mortality.ResultsThere were 15 935 participants who underwent colonoscopy (men, 59.7%; white, 90.7%; median age, 64 y [IQR, 61-68]). On initial colonoscopy, 2882 participants (18.1%) had an advanced adenoma, 5068 participants (31.8%) had a nonadvanced adenoma, and 7985 participants (50.1%) had no adenoma; median follow-up for CRC incidence was 12.9 years. CRC incidence rates per 10 000 person-years of observation were 20.0 (95% CI, 15.3-24.7; n = 70) for advanced adenoma, 9.1 (95% CI, 6.7-11.5; n = 55) for nonadvanced adenoma, and 7.5 (95% CI, 5.8-9.7; n = 71) for no adenoma. Participants with advanced adenoma were significantly more likely to develop CRC compared with participants with no adenoma (rate ratio [RR], 2.7 [95% CI, 1.9-3.7]; P < .001). There was no significant difference in CRC risk between participants with nonadvanced adenoma compared with no adenoma (RR, 1.2 [95% CI, 0.8-1.7]; P = .30). Compared with participants with no adenoma, those with advanced adenoma were at significantly increased risk of CRC death (RR, 2.6 [95% CI, 1.2-5.7], P = .01), but mortality risk in participants with nonadvanced adenoma was not significantly different (RR, 1.2 [95% CI, 0.5-2.7], P = .68).Conclusions and relevanceOver a median of 13 years of follow-up, participants with an advanced adenoma at diagnostic colonoscopy prompted by a positive flexible sigmoidoscopy result were at significantly increased risk of developing colorectal cancer compared with those with no adenoma. Identification of nonadvanced adenoma may not be associated with increased colorectal cancer risk.Trial registrationclinicaltrials.gov Identifier: NCT00002540.

Project description:Dietary fiber has been associated with a reduced risk of colorectal cancer. However, it remains unclear at which stage in the carcinogenic pathway fiber may act or which food sources of dietary fiber may be most beneficial against colorectal cancer development.The objective was to prospectively evaluate the association between dietary fiber intake and the risk of incident and recurrent colorectal adenoma and incident colorectal cancer.Study participants were identified from the intervention arm of the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Participants received flexible sigmoidoscopy at baseline and 3 or 5 y after. Dietary fiber intake was measured by using a self-reported dietary questionnaire. The colorectal cancer, incident adenoma, and recurrent adenoma analyses were based on 57,774, 16,980, and 1667 participants, respectively. Unconditional logistic regression was used to assess the risk of incident and recurrent adenoma, and Cox proportional hazards models were used to assess the risk of colorectal cancer across categories of dietary fiber intake, with adjustment for potential confounders.Elevated total dietary fiber intake was associated with a significantly reduced risk of incident distal colorectal adenoma (ORhighest vs. lowest tertile of intake: 0.76; 95% CI: 0.63, 0.91; P-trend = 0.003) but not recurrent adenoma (P-trend = 0.67). Although the association was not statistically significant for colorectal cancer overall (HR: 0.85; 95% CI: 0.70, 1.03; P-trend = 0.10), a reduced risk of distal colon cancer was observed with increased total fiber intake (HR: 0.62; 95% CI: 0.41, 0.94; P-trend = 0.03). Protective associations were most notable for fiber originating from cereals or fruit.This large, prospective study within a population-based screening trial suggests that individuals consuming the highest intakes of dietary fiber have reduced risks of incident colorectal adenoma and distal colon cancer and that this effect of dietary fiber, particularly from cereals and fruit, may begin early in colorectal carcinogenesis. This trial was registered at clinicaltrials.gov as NCT01696981.

Project description:ImportanceGuidelines recommend a 10-year rescreening interval after a colonoscopy with normal findings (negative colonoscopy results), but evidence supporting this recommendation is limited.ObjectiveTo examine the long-term risks of colorectal cancer and colorectal cancer deaths after a negative colonoscopy result, in comparison with individuals unscreened, in a large, community-based setting.Design, setting, and participantsA retrospective cohort study was conducted in an integrated health care delivery organization serving more than 4 million members across Northern California. A total of 1 251 318 average-risk screening-eligible patients (age 50-75 years) between January 1, 1998, and December 31, 2015, were included. The study was concluded on December 31, 2016.ExposuresScreening was examined as a time-varying exposure; all participants contributed person-time unscreened until they were either screened or censored. If the screening received was a negative colonoscopy result, the participants contributed person-time in the negative colonoscopy results group until they were censored.Main outcomes and measuresUsing Cox proportional hazards regression models, the hazard ratios (HRs) for colorectal cancer and related deaths were calculated according to time since negative colonoscopy result (or since cohort entry for those unscreened). Hazard ratios were adjusted for age, sex, race/ethnicity, Charlson comorbidity score, and body mass index.ResultsOf the 1 251 318 patients, 613 692 were men (49.0%); mean age was 55.6 (7.0) years. Compared with the unscreened participants, those with a negative colonoscopy result had a reduced risk of colorectal cancer and related deaths throughout the more than 12-year follow-up period, and although reductions in risk were attenuated with increasing years of follow-up, there was a 46% lower risk of colorectal cancer (hazard ratio, 0.54; 95% CI, 0.31-0.94) and 88% lower risk of related deaths (hazard ratio, 0.12; 95% CI, 0.02-0.82) at the current guideline-recommended 10-year rescreening interval.Conclusions and relevanceA negative colonoscopy result in average-risk patients was associated with a lower risk of colorectal cancer and related deaths for more than 12 years after examination, compared with unscreened patients. Our study findings may be able to inform guidelines for rescreening after a negative colonoscopy result and future studies to evaluate the costs and benefits of earlier vs later rescreening intervals.

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Predicting the risk of recurrent adenoma and incident colorectal cancer based on findings of the baseline colonoscopy.

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